2006 MERCEDES-BENZ SPRINTER air bleeding

As the dragging brake overheats, efficiency is so
reduced that fade occurs. Since the opposite brake
unit is still functioning normally, its braking effect is
magnified. This causes pull to switch direction in
favor of the normally functioning brake unit.
An additional point when diagnosing a change in
pull condition concerns brake cool down. Remember
that pull will return to the original direction, if the
dragging brake unit is allowed to cool down (and is
not seriously damaged).
REAR BRAKE GRAB OR PULL
Rear grab or pull is usually caused by improperly
adjusted or seized parking brake cables, contami-
nated lining, bent or binding shoes and support
plates, or improperly assembled components. This is
particularly true when only one rear wheel is
involved. However, when both rear wheels are
affected, the master cylinder or proportioning valve
could be at fault.
BRAKES DO NOT HOLD AFTER DRIVING THROUGH DEEP
WATER PUDDLES
This condition is generally caused by water soaked
lining. If the lining is only wet, it can be dried by
driving with the brakes very lightly applied for a
mile or two. However, if the lining is both soaked and
dirt contaminated, cleaning and/or replacement will
be necessary.
BRAKE LINING CONTAMINATION
Brake lining contamination is mostly a product of
leaking calipers or worn seals, driving through deep
water puddles, or lining that has become covered
with grease and grit during repair. Contaminated lin-
ing should be replaced to avoid further brake prob-
lems.
WHEEL AND TIRE PROBLEMS
Some conditions attributed to brake components
may actually be caused by a wheel or tire problem.
A damaged wheel can cause shudder, vibration and
pull. A worn or damaged tire can also cause pull.
Severely worn tires with very little tread left can
produce a grab-like condition as the tire loses and
recovers traction. Flat-spotted tires can cause vibra-
tion and generate shudder during brake operation. A
tire with internal damage such as a severe bruise,
cut, or ply separation can cause pull and vibration.
BRAKE NOISES
Some brake noise is common with rear drum
brakes and on some disc brakes during the first few
stops after a vehicle has been parked overnight or
stored. This is primarily due to the formation of trace
corrosion (light rust) on metal surfaces. This light
corrosion is typically cleared from the metal surfacesafter a few brake applications causing the noise to
subside.
BRAKE SQUEAK / SQUEAL
Brake squeak or squeal may be due to linings that
are wet or contaminated with brake fluid, grease, or
oil. Glazed linings and rotors with hard spots can
also contribute to squeak. Dirt and foreign material
embedded in the brake lining will also cause squeak/
squeal.
A very loud squeak or squeal is frequently a sign of
severely worn brake lining. If the lining has worn
through to the brake pads in spots, metal-to-metal
contact occurs. If the condition is allowed to continue,
rotors can become so scored that replacement is nec-
essary.
BRAKE CHATTER
Brake chatter is usually caused by loose or worn
components, or glazed/burnt lining. Rotors with hard
spots can also contribute to chatter. Additional causes
of chatter are out-of-tolerance rotors, brake lining not
securely attached to the shoes, loose wheel bearings
and contaminated brake lining.
THUMP / CLUNK NOISE
Thumping or clunk noises during braking are fre-
quentlynotcaused by brake components. In many
cases, such noises are caused by loose or damaged
steering, suspension, or engine components. However,
calipers that bind on the slide surfaces can generate
a thump or clunk noise.
STANDARD PROCEDURE
STANDARD PROCEDURE - MANUAL BLEEDING
Use approved brake fluid (Refer to LUBRICATION
& MAINTENANCE/FLUID TYPES - DESCRIP-
TION). Use fresh, clean fluid from a sealed container
at all times.
(1) Remove reservoir filler caps and fill reservoir.
(2) If calipers, or wheel cylinders were overhauled,
open all caliper and wheel cylinder bleed screws.
Then close each bleed screw as fluid starts to drip
from it. Top off master cylinder reservoir once more
before proceeding.
(3) Attach one end of bleed hose to bleed screw
and insert opposite end in glass container partially
filled with brake fluid (Fig. 1). Be sure end of bleed
hose is immersed in fluid.
5 - 4 BRAKES - BASEVA

(4) Open up bleeder, then have a helper press
down the brake pedal. Once the pedal is down closethe bleeder. Repeat bleeding until fluid stream is
clear and free of bubbles. Then move to the next
wheel.
STANDARD PROCEDURE - PRESSURE BLEED-
ING
Use approved brake fluid (Refer to LUBRICATION
& MAINTENANCE/FLUID TYPES - DESCRIP-
TION). Use fresh, clean fluid from a sealed container
at all times.
Follow the manufacturers instructions carefully
when using pressure equipment. Do not exceed the
tank manufacturers pressure recommendations. Gen-
erally, a tank pressure of 15-20 psi is sufficient for
bleeding.
Fill the bleeder tank with recommended fluid and
purge air from the tank lines before bleeding.
Do not pressure bleed without a proper master cyl-
inder adapter. The wrong adapter can lead to leak-
age, or drawing air back into the system.
HYDRAULIC / MECHANICAL
SPECIFICATIONS
SPECIFICATIONS - TORQUE CHART
TORQUE SPECIFICATIONS
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Brake Lines 14 Ð 124
Master Cylinder To Brake
Booster Nut28 Ð 248
Brake Caliper Adapter
Rear
M12 X 1.5 Bolt90 66 Ð
Brake Caliper Adapter
Rear
M14 X 1.5 Bolt170 125 Ð
Brake Caliper Adapter
Front170 125 Ð
Disc Brake Rotor Locking
Bolt
Front or Rear23 Ð 204
Wear Indicator To Caliper
Bolt
Front or Rear10 Ð 89
Pedal Bracket to Firewall 23 Ð 204
Fig. 1 Bleed Hose Setup
1 - BLEED HOSE
2 - FLUID CONTAINER PARTIALLY FILLED WITH FLUID
VABRAKES - BASE 5 - 5

(3) Check the brake system for any leaks.
(4) Reconnect the electrical connector to the brake
fluid level indicator (Fig. 14).
ALB LEVER
REMOVAL
(1) Raise and support the vehicle.
(2) Remove the retaining clip for the ALB lever
(Fig. 15).
(3) Remove the bolt for the lever at the axle (Fig.
15).
(4) Remove the lever.
INSTALLATION
(1) Install the lever to the vehicle.
(2) Install the lower mounting bolt to the axle (Fig.
15).
(3) Install the lever to the shock bolt and then
install the clip (Fig. 15).
(4) Check the side deflection of the ALB lever with
a straight edge from Point-A to Point-B as the
graphic shows. Max deflection play of the actuator
rod should be no more than 15 mm (.60 in) (Fig. 15).
(5) Lower the vehicle.
ALB CONTROLLER
REMOVAL
(1) Install the brake pedal rod to hold the brake
pressure.
(2) Raise and support the vehicle.(3) Remove the brake lines to the (automatic load-
dependant brake pressure control) ALB controller.
(4) Remove the adjusting nut and the spring from
the ALB controller.
(5) Remove the mounting bolts.
(6) Remove the ALB controller.
INSTALLATION
(1) Install the ALB controller to the vehicle.
(2) Install the mounting bolts for the controller.
(3) Install the brake lines. Tighten the lines to 16
N´m (142 in. lbs.)
(4) Install the adjusting rod, nut and spring to the
ALB controller.
(5) Lower the vehicle.
(6) Remove the brake pedal hold down rod.
(7) Fill and bleed the brake system (Refer to 5 -
BRAKES - STANDARD PROCEDURE).
(8) Raise the vehicle and adjust the ALB controller
(Refer to 5 - BRAKES/HYDRAULIC/MECHANICAL/
ALB CONTROLLER - ADJUSTMENTS).
(9) Lower the vehicle and test drive.
ADJUSTMENTS
ADJUSTMENT
(1) Clean any debris away from the test ports caps
at the ALB controller.
(2) Connect brake adapters special tool 9297 to the
test ports at the ALB controller.
(3) Install a Pressure Gauge, Special Tool
C-4007-A, to the adapters.
(4) Tighten all tube nut fittings to 17 N´m (145 in.
lbs.) torque.
(5) Bleed any air out of the system. This includes
bleeding the air from the hose between the pressure
test fitting and pressure gauge, which is done at the
pressure gauge.
NOTE: Adjustment is determined for the automatic
load-dependent brake power control system accord-
ing to the ALB plate. This is housed in the stowage
compartment under the front passenger's door
panel. The part number of the rear spring is
stamped into the spring eye. This must correspond
to the part number of the rear spring on the ALB
plate.
(6) To accurately adjust the rear axle load you
must first determine the rear axle load by weighing
the vehicle at a local scale.
(7) Install the brake pedal winch Special tool 9296
between the brake pedal and the driver seat and
slowly turn the dial until the specified inlet brake
pressure is indicated at the gauge.
Fig. 15 ALB LEVER DEFLECTION
1 - CLIP
2 - SPRING
3 - LEVER
4 - STRIAGHT EDGE
5 - NUT
6 - POINT -A
7 - POINT - B
8 - SUSPENSION POINT
5 - 16 BRAKES - BASEVA

(3) Use a hand operated vacuum pump for test.
(4) Apply 15-20 inches vacuum at large end of
check valve (Fig. 18).
(5) Vacuum should hold steady. If gauge on pump
indicates vacuum loss, check valve is faulty and
should be replaced.
STANDARD PROCEDURE - MASTER CYLINDER
BLEEDING
A new master cylinder should be bled before instal-
lation on the vehicle. Required bleeding tools include
bleed tubes and a wood dowel to stroke the pistons.
Bleed tubes can be fabricated from brake line.
(1) Mount master cylinder in vise.
(2) Attach bleed tubes to cylinder outlet ports.
Then position each tube end into reservoir (Fig. 19).
(3) Fill reservoir with fresh brake fluid.
(4) Press cylinder pistons inward with wood dowel.
Then release pistons and allow them to return under
spring pressure. Continue bleeding operations until
air bubbles are no longer visible in fluid.
REMOVAL
(1) Using a suction gun remove as much brake
fluid from the reservoir as possible (Fig. 20).
(2) Remove the fluid reservoir (Fig. 20) or (Fig. 21)
(Refer to 5 - BRAKES/HYDRAULIC/MECHANICAL/
FLUID RESERVOIR - REMOVAL).
(3) Remove the brake linesSeal off the ends and
bore holes with plugs.(Fig. 20) or (Fig. 21)
(4) Remove the master cylinder mounting nuts
(Fig. 20) or (Fig. 21).Check brake booster for
damage due to leaking master cylinder. It is not
possible to repair the master cylinder.
Fig. 18 Vacuum Check Valve And Seal
1 - BOOSTER CHECK VALVE
2 - APPLY TEST VACUUM HERE
3 - VALVE SEAL
Fig. 19 Master Cylinder Bleeding±Typical
1 - BLEEDING TUBES
2 - RESERVOIR
Fig. 20 MASTER CYLINDER
1 - SUCTION GUN
2 - BRAKE FLUID CAP
3 - BRAKE FLUID LEVEL INDICATOR
4 - O-RING
5 - NUT
6 - BRAKE LINE
7 - MASTER CYLINDER
8 - FLUID RESERVOIR
5 - 18 BRAKES - BASEVA